1. Field of the Invention
The present invention relates to a network control device used when a new different network system is connected to a conventional network system to extend the network system and, more particularly, to a technique for realizing space saving of a network system and reductions in cost and effort required for constructing the network system.
2. Description of the Related Art
Conventionally, when a new different network system B such as a high-speed digital network system constituted by a plurality of digital devices each having high-speed LAN interfaces is additionally connected to a conventional network system A such as an in-vehicle network system constituted by a plurality of analog devices each having a low-speed LAN (Local Area Network) interface, a device (network control device) having a gateway function is generally interposed between the networks A and B to control communication between the networks A and B (see Japanese Patent Application Laid-Open No. 7-95659).
However, when a network system is extended by a conventional method, a new device used for only communication between networks is added to the network system. For this reason, the scale of the network system is enlarged, and it is very difficult to realize space saving of the network system as a whole.
In addition, when the network system is extended, a new device used for only communication is added to increase a cost required for constructing the network system and to increase the number of steps in design. Some change and addition must be performed to a conventional device, disadvantageously.
The present invention has been made in consideration of the above-mentioned technical problems, and has as its object to provide a network system control device for realizing space saving of a network system and reductions in cost and effort required for constructing the network system.
In order to achieve the object, as a characteristic feature of the present invention, there is provided a network control device comprising: network control unit for controlling a communication process in a first network system; a serial interface for controlling a serial communication process between the first network system and a second network system; and initializing unit for updating a communication program of the second network system, wherein the initializing unit has mode switching unit for switching changeable/unchangeable of the communication program of the second network system, and program download unit for transmitting the communication program to the second network system.
According to the embodiment of the present invention, a new different network system is added to a conventional network system such as an in-vehicle network system without using a device having a conventional gateway function and without changing a conventional device at all, so that the network system can be extended. For this reason, space saving of the network system and a reduction in cost required for constructing the network system can be realized. In addition, the network control device may have only a simple serial interface and need not have an interface related to a conventional network, so that the software related to network control can be easily designed. In addition, since all the device on the network system can be operated by transmitting/receiving a simple command using serial communication, an extending operation for the network system can be easily performed.
The network control device has a function included in the present invention, so that communication between different networks may be realized while saving the space.
In this manner, since a device having a gateway function need not be added when a network is constructed, the network can be easily extended while extending the scale of the network.
The network control device has a function included in the present invention, so that communication between different networks may be realized without changing a conventional device at all.
In this manner, since a conventional device need not be changed when a network is constructed, a cost required for constructing the network system and the number of steps in design can be considerably reduced.